August 11, 2008
Vitamin D Reduces Death Rate

Time for another in my continuing saga of why you need to get a lot of vitamin D. While previous studies have found evidence that higher vitamin D concentrations reduce the risk of death Johns Hopkins researchers think their new study is a big and sufficiently well controlled study to finally feel confident that vitamin D cuts death rates.

Researchers at Johns Hopkins are reporting what is believed to be the most conclusive evidence to date that inadequate levels of vitamin D, obtained from milk, fortified cereals and exposure to sunlight, lead to substantially increased risk of death.

In a study set to appear in the Archives of Internal Medicine online Aug. 11, the Johns Hopkins team analyzed a diverse sample of 13,000 initially healthy men and women participating in an ongoing national health survey and compared the risk of death between those with the lowest blood levels of vitamin D to those with higher amounts. An unhealthy deficiency, experts say, is considered blood levels of 17.8 nanograms per milliliter or lower.

Of the 1,800 study participants known to have died by Dec. 31, 2000, nearly 700 died from some form of heart disease, with 400 of these being deficient in vitamin D. This translates overall to an estimated 26 percent increased risk of any death, though the number of deaths from heart disease alone was not large enough to meet scientific criteria to resolve that it was due to low vitamin D levels.

Yet, researchers say it does highlight a trend, with other studies linking shortages of vitamin D to increased rates of breast cancer and depression in the elderly. And earlier published findings by the team, from the same national study, have established a possible tie-in, showing an 80 percent increased risk of peripheral artery disease from vitamin D deficits.

Breast cancer, depression, and peripheral artery disease should be on everyone's list of things to avoid.

Hey, they did a big study and have clearer results than other studies. So they are bragging. But they deserve to brag. So why not?

Researchers note that other studies in the last year or so in animals and humans have identified a connection between low levels of vitamin D and heart disease. But these studies, they say, were weakened by small sample numbers, lack of diversity in the population studied and other factors that limited scientists' ability to generalize the findings to the public at large.

"Our results make it much more clear that all men and women concerned about their overall health should more closely monitor their blood levels of vitamin D, and make sure they have enough," says study co-lead investigator Erin Michos, M.D., M.H.S.

Small amounts of sunlight can make the difference. Though in winter better think about taking a vitamin D pill. Your benefit probably tops out at 2000 IU per day. Though only a blood test would tell you whether you are at the 50 nanograms per milliliter concentration at which benefit is maximized.

Aware of the cancer risks linked to too much time spent in the sun, she says as little as 10 to 15 minutes of daily exposure to the sun can produce sufficient amounts of vitamin D to sustain health. The hormone-like nutrient controls blood levels of calcium and phosphorus, essential chemicals in the body.

If vitamin supplements are used, Michos says there is no evidence that more than 2,000 international units per day do any good. Study results show that heart disease death rates flattened out in participants with the highest vitamin D levels (above 50 nanograms per milliliter of blood), signaling a possible loss of the vitamin's protective effects at too-high doses.

The U.S. Institute of Medicine suggests that an adequate daily intake of vitamin D is between 200 and 400 international units (or blood levels nearing 30 nanograms per milliliter). Previous results from the same nationwide survey showed that 41 percent of men and 53 percent of women are technically deficient in the nutrient, with vitamin D levels below 28 nanograms per milliliter.

Are you still not taking vitamin D? If not, what's your problem? Secret death wish? A feeling of futility? Or maybe you are one of those rare people who like having doctors fuss all over you? In that case it is safer to use fake symptoms. So take the vitamin D anyhow.

Share |      Randall Parker, 2008 August 11 11:06 PM  Aging Diet Studies

Jake said at August 12, 2008 7:54 AM:

If you are over 60, your body has lost its ability to make Vitamin D from sunlight. You must take Vitamin D3 supplements.

Nick G said at August 12, 2008 2:50 PM:

Jake, do you have sources for that? That's an extremely important question - many of us have parents in Florida or Arizona over age 60, and are assuming they get all they need from sunshine. If you're right, they need to take supplements ASAP.

So - can you point us to a source or two?

Michael G.R. said at August 12, 2008 9:04 PM:

If you take vit D supplements, make sure you get gelcaps and not dry tablets. Vit D is fat-soluble, and is not as well absorbed with dry pills according to Dr. William Davis ( He does blood tests, and has found that some of his patients who took dry (not gelcaps) supplement of vit D showed almost no increase in blood levels. A switch to gelcaps fixed the problem.

Nick G said at August 13, 2008 1:17 PM:

"If you are over 60, your body has lost its ability to make Vitamin D from sunlight."

Well, I did some research, and info is all over the map. Some say absorption is reduced by 75% over age 65, but don't give evidence. One study found that reduced absorption was correlated with skin thickness, which falls with age.

It does look like supplements might be a good idea for the elderly, even in the South, though I imagine that some sun-aholics will get enough. If the Southern elderly are even partially disabled, and mostly indoors, they very likely need supplements.

LIZZI said at August 14, 2008 10:07 AM:

Again, this is an association study. The people studied were not on Vitamin D supplements. The association between low D and cardiovascular disease was not statistically significant. Don't get me wrong, there may be cause and effect here, its plausible, I hope so. We're just not there yet. I hope that vitamin D supplementation will not end up just clearing up the smoke from the smoking gun of age related killer diseases. It is worrysome that there was a negative correlation over Vitamin D levels above 50. How many people are willy nilly supplementing to levels of 70 without getting their 25 OH Vitamin D levels checked? Medicare keeps trying not to pay for the test, secondary insurance usually pays for it, labcorp charges $270.00 for a 25-OH Vitamin D level. Randall, how hard would it be to take 100 chronic pain patients, measure their Vit D levels, randomize and double blind the researchers, give half of them 2,000 of D and half of them placebo, and see if there is a significant change in pain score or narcotics use in 6 months? Pain may be relatively easy and cheap to explore. Cardiovascular disease and cancer will be much, much more costly and difficult. And there is no drug company to help foot the bill. I hope the NIH steps up.

Nick G said at August 14, 2008 10:57 AM:

"there was a negative correlation over Vitamin D levels above 50"

I don't think that's what they said. This quote: "heart disease death rates flattened out in participants with the highest vitamin D levels" suggests that there was no additional benefit (and no harm) from D levels above 50. In other words, the only harm from too much D is spending a little too much money on supplements.

Randall Parker said at August 14, 2008 6:53 PM:

Nick G,

I also have read claims in the past that vitamin D production drops in old skin. I do not know whether this has been proven. It'd be worth emailing Michael Holick or Cedric Garland at UC San Diego. Garland has posted in the comments of a previous Vitamin D post I did. Maybe he'll see this and comment.


Randomized interventions cost a lot more per person. Doable. These association studies build up the case for intervention studies. Small association studies lead to bigger association studies that lead to small and large intervention studies. I'm frustrated at the pace of this for vitamin D since at each step the results look so promising.

Ardie said at January 29, 2010 6:21 AM:

Many diseases like pancreatic cancer, childhood diabetes have been linked to a virus (research has also shown that viruses alter our DNA). But research has also shown that Vitamin D3 (actually a hormone) is a potent antibiotic that works by increasing the body's production of antimicrobial peptides that can destroy the cell walls of viruses, bacteria and fungi—even the influenza virus. On this same score, most people have inadequate stores of Vitamin D3 in their body. In other words, they are Vitamin D3 deficient. This is especially true of people who live in regions of diminished sunlight and/or people who over use sun screens.

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